What a beast, I'm so jealous!

I wouldn't bother with a heat mat, they're not ideal and more trouble than what they're worth. In order to use it, you'd actually need a thermostat to control it and a digital thermometer to measure the temps, as it will most likely get to 100oF unstatted.

Low wattage ceramic heat emitters or red bulbs work great for night heat. For my horned frog I use a Zoo Med red night light bulb on a dimmer thermostat that will automatically lower the temps at night so I can use it 24/7. In order to create a day and night cycle I have a UV bulb right next to it